As the 2009 Amsoil/Mopar Muscle Engine Challenge has proven, it's difficult to beat the low-deck stroker, and more specifically the Chrysler 400 block with a factory 440 crank, when it comes to power per dollar. All of this year's competitors were required to build a low-deck big-block for our annual contest, and all of the engine builders chose a factory 400 block for its large bore size. Builders were also required to run Edelbrock's Performer RPM cylinder heads, but could port and otherwise modify the heads pretty much any way they chose. All of the engines were lubricated with Amsoil 10W40 synthetic oil, and Rockett Brand supplied the 93 octane unleaded fuel for our competition, requiring the engine builders keep compression at a street-friendly level. About the only other limitation in our rules was induction which was restricted to a total of 1,350 cfm.

2/27LaRoy Engines and ProMax Performance finished third and fourth respectively in the....

The dyno portion of the Engine Challenge is held at Comp Cams' Memphis, Tennessee, research facility, and each engine is required to make three qualifying, then three judged dyno pulls between 3,000 and 7,000 rpm. The combined peak power and torque of the engine's single best pull is then factored into the cost of the engine's parts, for a power per dollar factor to determine the winner. Since we're all feeling the effects of the economy these days, this year's rules factored used parts at their fair market value, showing that a powerful engine could be built with a combination of new and "seasoned" items.

LaRoy Engines of Challis, Idaho, finished third in the 2009 contest, and ProMax Performance of Indianapolis, Indiana, finished a strong forth. Each of these engines combined power and economics to gain an advantage, both completing all of their pulls without incident. The father and son team of Jim and Cody LaRoy impressed everyone in attendance with their big horsepower numbers, and ProMax Performance made a solid showing with their economically built big-block. This month we'll show you what parts and techniques the third and forth place engine builders used to tweak big power from these Mopar V-8s.

3/27....2009 Amsoil/Mopar Muscle Engine Challenge. This month we'll go inside their powerful big-blocks and show you how they did it.

LaRoy Engines
Challis, Idaho
As a small engine shop in rural Idaho, LaRoy Engines was a newcomer to our contest this year. Specializing in powerful Mopar engines, LaRoy Engines places high emphasis on accurate machining and porting cylinder heads for maximum flow. Though the LaRoys are too busy building engines to do much racing, Jim LaRoy did enter the 2008 DynoMax "Power to the Wheels" contest, placing third in the normally-aspirated class behind two other Mopars. For this year's Engine Challenge, father and son team Jim and Cody LaRoy decided rather than strictly going for the win by building a powerful budget motor, they'd rather show how much horsepower they could make while staying within our somewhat restrictive rules, building an all-out 452-inch pump-gas powerhouse.

On the dyno at Comp, the LaRoy entry fired immediately, sounding crisp and powerful. During their qualifying dyno pulls, Jim and Cody LaRoy tuned their engine for the weather conditions and headers of Comp's dyno cell, efficiently making more power with each pull. As one of the smallest displacement engines in the contest, this big-block got everyone's attention as it made consistent pulls at 700 plus horsepower. Through a series of air-bleed, jet, and ignition timing changes, Jim and Cody LaRoy netted a best pull of 723.4 horsepower and 568.8 lb/ft of torque for an impressive combined score of 1,292.2. Also noteworthy was the fact that this engine made an impressive 1.6 horsepower per cubic inch, the highest in the contest by that standard. Only one of this year's entries made more horsepower, one more, and it was some 50 cubic inches larger.

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Starting with a factory 400 block, LaRoy Engines had all the necessary machine work performed to accommodate a forged Chrysler 440 crankshaft and Ross forged flat-top pistons. Scat forged H-beam connecting rods were used for their strength and relative light weight, and Total-Seal piston rings were used to seal the cylinders. The rotating assembly was balanced and a Professional Products SFI-approved damper was utilized. An Erson roller camshaft was matched to a set of Comp Cams solid roller lifters for well over .700 inch of total valve lift, and a power curve that was still increasing at the 7,000 rpm limit of the competition. To handle engine lubrication, a Melling high-volume oil pump was utilized along with a stock, 4-quart oil pan, and Jim LaRoy fabricated a crankshaft scraper from a stock windage tray.

11/27Since there were no acceleration forces on the dyno, the LaRoys chose a stock 4 quart oil pan with baffles to keep....

Edelbrock Performer RPM cylinder heads were the required heads for this year's challenge, and our rules allowed pretty much any modification other than welding the heads or moving the rocker location. LaRoy Engines specializes in cylinder head porting, and Cody LaRoy worked his magic on these cylinder heads, netting an amazing 349 cfm of flow at .800 lift on the intake side. Even more impressive, these flow numbers were accomplished with no epoxy modifications whatsoever. In addition to porting, these heads were cut to accommodate 2.25-inch Manley stainless steel intake valves and Comp Cams PN 951 valvesprings with titanium retainers. 440Source supplied the 1.6 ratio roller rocker arms, and a used Indy 4500 flange single-plane intake was matched with an 1,150 cfm Pro Systems Series XC carburetor. Ignition was handled by a Summit Racing electronic distributor wired to the dyno's MSD ignition box.

ProMax Performance
Indianapolis, Indiana
Located in Indianapolis, Indiana, the racing capital of the world, and with an address right on Gasoline Alley, ProMax Performance is no stranger to powerful engines. While they began as a carburetor shop known for tuning, modifying, and manufacturing single and multiple carbs and parts, ProMax now offers an array of services including engine building and dyno testing. Owner and engine builder Ben Gorman loves the automotive industry, and he and his employees campaign three active Mopar race cars as well as sponsoring the ProMax fastest street car shootout. For this year's contest, ProMax built an economical 451-inch big-block, making nearly 570 horsepower for a fourth place finish.

12/27....windage at a minimum. To help, a crank scraper was fabricated from a factory big-block windage tray.

On the dyno, the ProMax entry performed flawlessly, making all of its pulls with ease. Starting with 36 degrees of ignition timing, the ProMax crew quickly tuned their engine to additional power by bumping timing to 38, then 40 degrees of total advance. During their qualifying and judged pulls, ProMax utilized one of their blueprinted Holley 850 carbs to show the potential of their product. After their best pull of 568.9 horsepower and 518.1 lb/ft of torque, Ben changed to a Holley 950, losing power and torque across the board. We've always known these guys have a knack at tuning and building carbs, and the dyno backed up our opinion.

Using a factory Chrysler 400 block as the basis for this engine, ProMax machined the block for a stock 440 crank, giving the engine a stroke of 3.75 inch. Diamond PN 52007 forged flat-top pistons were hung on Eagle forged steel H-beam connecting rods, and the rotating assembly was balanced. Clevite engine bearings and Total Seal piston rings were utilized in this engine, along with a PRW PN 2444001 SFI approved balancer. A Melling PN M63HV oil pump was combined with a factory Hemi oil pan and Milodon windage tray to keep the engine sufficiently lubricated. Comp Cams' PN 23-362-5 flat-tappet camshaft was used with Comp solid lifters, spun by Comp's PN 2104 double-roller timing set. A factory Chrysler electronic distributor was used to ignite the mixture, performing flawlessly to 7,000 rpm.

13/27Edelbrock-installed exhaust valves were used in these heads, but the intake seats were cut for 2.25-inch Manley stainless steel valves.

To optimize their combination, ProMax ported their Edelbrock Performer RPM heads in-house, keeping the runner volume reasonable, to match their flat-tappet camshaft. By not porting for maximum flow, ProMax sacrificed a little peak power, but made up for it with smooth and broad torque and horsepower curves. To save costs, the Edelbrock 2.14-inch intake and 1.81-inch exhaust valves were retained, along with the Edelbrock valvesprings. This choice, along with factory-style adjustable rocker gear, kept the cost of this engine reasonable, which was important to finish well this year. To feed this 451-inch big-block, ProMax chose an Edelbrock PN 2886 Victor intake manifold and a ProMax custom blueprinted 850 carb. At 568.9 horsepower and 518.1 lb/ft of torque, this engine is a stout performer, placing fourth in the 2009 Amsoil/Mopar Muscle Engine Challenge.

What's Up for 2010
The rules for the 2010 contest are posted on the website, so be sure to check them. In 2010, our dyno contest will feature the small-block Mopar with RHS cylinder heads, and it will be a horsepower per cubic inch shootout. We love diversity in our contest and accept applications from engine builders throughout the country. We don't care if you're running a huge production shop or if you're building Mopar engines in your garage.

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For more information, be sure to check out www.moparmusclemagazine.com. We have even set up a Forum Section for you guys to talk to each other, ask questions, or just talk smack before the challenge. Check out the Forum in the Mopar Muscle magazine section.